package week5;

/**
 * Created by Administrator on 2016/3/30.
 */
public class StackTraceDemo {
    public static void main(String[] args) {
        try {
            c();
        }catch (NullPointerException ex){
            ex.printStackTrace();;
        }
    }
    static void c(){
        b();
    }
    static void b(){
        a();
    }
    static String a(){
        String text = null;
        return text.toUpperCase();
    }
}
